The invention relates to systems for analyzing and sorting particles according to selected characteristics.
Systems for sorting various types of particulate matter are well-known and have been used commercially for a variety of purposes such as quality control in the final inspection of grains and other free-flowing granular products. Their function, primarily, is to sort out and remove foreign or non-conforming material from the final product. To achieve this end, a combination of mechanical, optical, electronic and pneumatic components somewhat comparable to the components used in the present system usually are employed.
In other respects, however, they differ significantly from the present system. Thus, as will be described, the present system is concerned more directly with a relatively detailed and sophisticated analysis of each individual particle rather than with the somewhat cursory procedures used for quality control. For example, one of its primary uses is in the field of micropaleontology where a fairly large and varied amount of data must be obtained for each particle. In particular, it has been used for a rather voluminous study of the shell structures of foraminafera, although a wide variety of other uses clearly is contemplated. Quality control machines, in contrast, are designed to rather quickly distinguish the `good` from the `bad` according to one or two easily and simply determined characteristics. Their emphasis is upon speed or high handling rates and, to achieve this end, it is customary to examine and sort the particles as they are moved in a flowing stream past a viewing system which receives light reflected from the particles and passes it to detectors such as photomultipliers or the like.
In the present system, the emphasis instead is upon a programmed and relatively detailed `look` at each particle and such a `look` cannot be obtained if the particles are moving in a steady flow past the viewer. Each particle, therefore, is stopped for the examination. Further, each must be stopped in a precise position which permits the viewing mechanism to be finely focussed and also, preferably, in a position in which the particles can be viewed from several different angles needed to analyze different characteristics. In the present system, therefore, such matters as particle feed and handling which must be precise, reliable and efficient. Also, it is concerned with a complete automation of the handling as well as the anaylsis itself so as to provide a system that can operate unattended for the long periods of time needed to obtain the rather voluminous data needed for the study. As will be described, computer technology presently is using both to control and to synchronize all of the mechanical aspects of the system as well as the particle analysis. As far as is known, prior art systems have not employed comparable controls or, in fact, comparable handling and viewing mechanisms.